// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2014 Benoit Steiner <benoit.steiner.goog@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_FIXEDSIZEVECTOR_H
#define EIGEN_FIXEDSIZEVECTOR_H

namespace Eigen {

/** \class MaxSizeVector
  * \ingroup Core
  *
  * \brief The MaxSizeVector class.
  *
  * The %MaxSizeVector provides a subset of std::vector functionality.
  *
  * The goal is to provide basic std::vector operations when using
  * std::vector is not an option (e.g. on GPU or when compiling using
  * FMA/AVX, as this can cause either compilation failures or illegal
  * instruction failures).
  *
  * Beware: The constructors are not API compatible with these of
  * std::vector.
  */
template <typename T> class MaxSizeVector
{
    static const size_t alignment = EIGEN_PLAIN_ENUM_MAX(EIGEN_ALIGNOF(T), sizeof(void*));

public:
    // Construct a new MaxSizeVector, reserve n elements.
    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE explicit MaxSizeVector(size_t n)
        : reserve_(n), size_(0), data_(static_cast<T*>(internal::handmade_aligned_malloc(n * sizeof(T), alignment)))
    {
    }

    // Construct a new MaxSizeVector, reserve and resize to n.
    // Copy the init value to all elements.
    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE MaxSizeVector(size_t n, const T& init)
        : reserve_(n), size_(n), data_(static_cast<T*>(internal::handmade_aligned_malloc(n * sizeof(T), alignment)))
    {
        size_t i = 0;
        EIGEN_TRY
        {
            for (; i < size_; ++i) { new (&data_[i]) T(init); }
        }
        EIGEN_CATCH(...)
        {
            // Construction failed, destruct in reverse order:
            for (; (i + 1) > 0; --i) { data_[i - 1].~T(); }
            internal::handmade_aligned_free(data_);
            EIGEN_THROW;
        }
    }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE ~MaxSizeVector()
    {
        for (size_t i = size_; i > 0; --i) { data_[i - 1].~T(); }
        internal::handmade_aligned_free(data_);
    }

    void resize(size_t n)
    {
        eigen_assert(n <= reserve_);
        for (; size_ < n; ++size_) { new (&data_[size_]) T; }
        for (; size_ > n; --size_) { data_[size_ - 1].~T(); }
        eigen_assert(size_ == n);
    }

    // Append new elements (up to reserved size).
    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void push_back(const T& t)
    {
        eigen_assert(size_ < reserve_);
        new (&data_[size_++]) T(t);
    }

    // For C++03 compatibility this only takes one argument
    template <class X> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void emplace_back(const X& x)
    {
        eigen_assert(size_ < reserve_);
        new (&data_[size_++]) T(x);
    }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const T& operator[](size_t i) const
    {
        eigen_assert(i < size_);
        return data_[i];
    }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T& operator[](size_t i)
    {
        eigen_assert(i < size_);
        return data_[i];
    }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T& back()
    {
        eigen_assert(size_ > 0);
        return data_[size_ - 1];
    }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const T& back() const
    {
        eigen_assert(size_ > 0);
        return data_[size_ - 1];
    }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void pop_back()
    {
        eigen_assert(size_ > 0);
        data_[--size_].~T();
    }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE size_t size() const { return size_; }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool empty() const { return size_ == 0; }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T* data() { return data_; }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const T* data() const { return data_; }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T* begin() { return data_; }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T* end() { return data_ + size_; }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const T* begin() const { return data_; }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const T* end() const { return data_ + size_; }

private:
    size_t reserve_;
    size_t size_;
    T* data_;
};

}  // namespace Eigen

#endif  // EIGEN_FIXEDSIZEVECTOR_H
